www.pudn.com > MultiDragImg_src.zip > CListCtrlEx.cpp

CImageList *CListCtrlEx::CreateDragImageEx( LPPOINT lpPoint ) 
{ 
	CRect	cSingleRect;	 
	CRect	cCompleteRect( 0,0,0,0 ); 
	int		nIdx; 
	BOOL	bFirst = TRUE; 
 
	// 
	// Determine the size of the drag image  
	// 
	POSITION pos = GetFirstSelectedItemPosition(); 
	while (pos) 
	{ 
		nIdx = GetNextSelectedItem( pos ); 
		GetItemRect( nIdx, cSingleRect, LVIR_BOUNDS ); 
		if (bFirst) 
		{ 
			// Initialize the CompleteRect 
			GetItemRect( nIdx, cCompleteRect, LVIR_BOUNDS ); 
			bFirst = FALSE; 
		} 
		cCompleteRect.UnionRect( cCompleteRect, cSingleRect ); 
	} 
 
	// 
	// Create bitmap in memory DC 
	// 
	CClientDC	cDc(this);	 
	CDC 		cMemDC;	 
	CBitmap		cBitmap; 
 
	if(!cMemDC.CreateCompatibleDC(&cDc))		 
		return NULL;	 
 
	if(!cBitmap.CreateCompatibleBitmap(&cDc, cCompleteRect.Width(), cCompleteRect.Height())) 
		return NULL; 
	 
	CBitmap* pOldMemDCBitmap = cMemDC.SelectObject( &cBitmap ); 
	// Here green is used as mask color 
	cMemDC.FillSolidRect(0,0,cCompleteRect.Width(), cCompleteRect.Height(), RGB(0, 255, 0));  
 
	// 
	// Paint each DragImage in the DC 
	// 
	CImageList *pSingleImageList; 
	CPoint		cPt; 
 
	pos = GetFirstSelectedItemPosition(); 
	while (pos) 
	{ 
		nIdx = GetNextSelectedItem( pos ); 
		GetItemRect( nIdx, cSingleRect, LVIR_BOUNDS ); 
 
		pSingleImageList = CreateDragImage( nIdx, &cPt); 
		if (pSingleImageList) 
		{ 
			pSingleImageList->DrawIndirect( &cMemDC,  
											0,  
											CPoint( cSingleRect.left-cCompleteRect.left,  
													cSingleRect.top-cCompleteRect.top ), 
											cSingleRect.Size(),  
											CPoint(0,0)); 
			delete pSingleImageList; 
		} 
	} 
 
	cMemDC.SelectObject( pOldMemDCBitmap ); 
	// 
	// Create the imagelist	with the merged drag images 
	CImageList* pCompleteImageList = new CImageList; 
	 
	pCompleteImageList->Create(cCompleteRect.Width(),  
							   cCompleteRect.Height(),  
							   ILC_COLOR | ILC_MASK, 0, 1); 
	// Here green is used as mask color 
	pCompleteImageList->Add(&cBitmap, RGB(0, 255, 0));  
 
	cBitmap.DeleteObject(); 
	// 
	// as an optional service: 
	// Find the offset of the current mouse cursor to the imagelist 
	// this we can use in BeginDrag() 
	// 
	if ( lpPoint ) 
	{ 
		CPoint cCursorPos; 
		GetCursorPos( &cCursorPos ); 
		ScreenToClient( &cCursorPos ); 
		lpPoint->x = cCursorPos.x - cCompleteRect.left; 
		lpPoint->y = cCursorPos.y - cCompleteRect.top; 
	} 
 
	return( pCompleteImageList ); 
}